Monday, 16 February 2015

Eidsvold Earthquake 2015

I woke this morning to the news that a town to the west of Bundaberg had experienced a substantial earthquake. Well, substantial by Australian standards anyway. Geoscience Australia gives the intensity of 5.2 on the Richter scale. The quake occurred at about 2am local time (3am for those of us in the other eastern states coping with daylight saving).

The preliminary report from Geoscience Australia can be found here.
Seismograph from Eidsvold Station
It is in an interesting area because the area of the earthquake is in the northern part of the New England Orogen. This belt of squashed rocks extends from the Bundaberg area in a big arc all the way to Port Macquarie in the South. There are many faults in this area and some are still active, although they are generally small. An earthquake between Gunnedah and Tamworth in 2013 springs to mind.

The scale of the earthquake is quite large for Australia. Indeed the Newcastle earthquake was measured at 5.6. I've not done the maths but the new Eidsvold quake of 5.2 is about half the size of the Newcastle one (The Richter Scale is NOT linear).

Historically, the area is prone to small to medium sized earthquakes with Bundaberg being hit by a size 6.0 in 1918. This is nearly ten times more powerful than the most recent one though the 1918 quake occurred just off the coast.

Oh... and humour starts quickly: